Inflaton Regeneration via Scalar Couplings: Generic Models and the Higgs Portal

Fuente: arXiv
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Main Authors: Kaneta, Kunio, Takahashi, Tomo, Watanabe, Natsumi
Format: Preprint
Published: 2026
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author Kaneta, Kunio
Takahashi, Tomo
Watanabe, Natsumi
author_facet Kaneta, Kunio
Takahashi, Tomo
Watanabe, Natsumi
contents The standard cosmological paradigm assumes that the inflaton field becomes dynamically negligible during the post-reheating evolution of the Universe. We demonstrate that this assumption fails for a broad class of inflationary models where the potential behaves as a monomial form $V(ϕ) \propto ϕ^k$ (with $k \ge 4$) around the minimum. In such scenarios, the effective inflaton mass depends on the field amplitude and vanishes asymptotically as the Universe expands. This vanishing-mass mechanism renders the inflaton kinematically accessible to the thermal plasma long after reheating, facilitating the regeneration of inflaton quanta through 1-to-2 decays and 2-to-2 scatterings of bath particles. This mechanism is quite generic and the coupling responsible for reheating can be constrained if the inflaton is overproduced, while the inflaton quanta can constitute dark matter in specific scenarios. Furthermore, if reheating occurs via the Standard Model Higgs portal, the process can be further constrained by big bang nucleosynthesis, cosmic microwave background, and colliders such as the LHC. This mechanism provides a new framework for probing post-inflationary reheating.
format Preprint
id arxiv_https___arxiv_org_abs_2604_14620
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Inflaton Regeneration via Scalar Couplings: Generic Models and the Higgs Portal
Kaneta, Kunio
Takahashi, Tomo
Watanabe, Natsumi
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
The standard cosmological paradigm assumes that the inflaton field becomes dynamically negligible during the post-reheating evolution of the Universe. We demonstrate that this assumption fails for a broad class of inflationary models where the potential behaves as a monomial form $V(ϕ) \propto ϕ^k$ (with $k \ge 4$) around the minimum. In such scenarios, the effective inflaton mass depends on the field amplitude and vanishes asymptotically as the Universe expands. This vanishing-mass mechanism renders the inflaton kinematically accessible to the thermal plasma long after reheating, facilitating the regeneration of inflaton quanta through 1-to-2 decays and 2-to-2 scatterings of bath particles. This mechanism is quite generic and the coupling responsible for reheating can be constrained if the inflaton is overproduced, while the inflaton quanta can constitute dark matter in specific scenarios. Furthermore, if reheating occurs via the Standard Model Higgs portal, the process can be further constrained by big bang nucleosynthesis, cosmic microwave background, and colliders such as the LHC. This mechanism provides a new framework for probing post-inflationary reheating.
title Inflaton Regeneration via Scalar Couplings: Generic Models and the Higgs Portal
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2604.14620